This invention relates to electrical junction boxes and specifically to an electrical box mounting assembly for mounting a fan or light fixture to a ceiling.
Electrical boxes are commonly mounted on ceilings for the purpose of supporting ceiling fans, light fixtures, or other electrical devices. The electrical box provides a safe enclosure to house all wiring connections. Typically, these electrical boxes are secured to the ceiling by a supporting device that spans between two adjacent ceiling joists.
Various considerations are necessary in providing supporting devices for ceiling-mounted electrical boxes. The National Electrical Code specifies a maximum weight of 80 pounds for ceiling light fixtures and a maximum weight of 70 pounds for ceiling fans. It is therefore very important that an installer use adequate load-bearing fasteners for securing the supporting device to the overhead joists. It is also important that the load be carried by the supporting device, and not by the electrical box.
A second consideration arises from the awkwardness of working overhead. Typically, when securing a supporting device and an electrical box to the overhead structure of the ceiling, several separate items must be manipulated. These include the mounting bar, the electrical box, the fasteners for securing the mounting bar to the ceiling structure, and the fasteners for mounting the electrical box to the mounting bar. Considering that the installer is typically on a ladder, this creates a challenging task for any installer. It is therefore imperative that all parts necessary for a successful installation are on hand for the installer.
Another consideration is that the support device must be matched to an electrical box. Many supporting devices are meant to accommodate most commercial electrical boxes. This typically requires complex arrangements on the supporting device to accommodate a variety of boxes.
Many supporting devices for ceiling fans and fixtures include an arrangement to temporarily secure the device to the ceiling joists including U.S. Pat. No. 5,934,631 to Becker, et al., U.S. Pat. No. 5,954,304 to Jorgensen, U.S. Pat. No. 5,938,157 to Reiker, and U.S. Pat. No. 6,098,945 to Korcz, and U.S. Pat. No. 6,332,597 to Korcz et al.
Although all of the above supporting devices include an arrangement for temporarily fastening the supporting device to overhead joists to free up an installer""s hands, they are still not completely satisfactory for simplifying the remainder of the task for installing the electrical box and the light fixture or fan to the supporting device.
The invention is an adjustable mounting bar and electrical box assembly for hanging a light fixture, fan, or other electrical device from a ceiling. All hardware required for mounting the electrical device is included with the assembly. The adjustable mounting bar includes sliding tubular members with end flanges for spanning between adjacent overhead joists. An electrical box is connected to the tubular members by a clamp and outer clamping fasteners, which can be loosened to adjust the length of the adjustable mounting bar. The end flanges include penetrable tabs that can be driven into the overhead joists to temporarily secure the adjustable mounting bar to the joists and thereby free the installer""s hands. First load bearing fasteners are threadably engaged in first storage receptacles in the sliding tubular members of the assembly and upon temporary securement to the joists, can be removed from the storage receptacles and fastened through the end flanges to securely fasten the mounting bar to the joists. The assembly includes second load bearing device fasteners that are threadably engaged in second storage receptacles in the electrical box. After the mounting bar is secured to the joists and the electrical box is secured to the mounting bar, the device fasteners can be removed from the second storage receptacles and an electrical device brought into engagement with the lower edge of the electrical box. The device fasteners are then driven into receptacles in the clamp. Oversize openings are provided in the top wall of the electrical box to ensure that the entire suspended load is borne by the clamp and mounting bar and not the electrical box.
The electrical box mounting assembly of the present invention provides a complete mounting assembly for mounting an electrical device to a ceiling, including all of the required fastening hardware. All of the installation hardware that is required to complete the task is provided as a part of the mounting assembly, including all required fasteners.
An additional advantage is that the required fasteners are held securely in the electrical box mounting assembly in temporary storage receptacles. The temporary storage receptacles provide an advantage in that the fasteners are held securely in the assembly until they are ready to be used. The required fastening hardware is therefore on hand for installation at the time it is required. By freeing up an installer""s hands, the task of mounting an electrical device to a ceiling is therefore greatly simplified and the installation time greatly reduced. Additionally, by having all of the required fastening hardware on hand, the installer is not burdened by the task of locating appropriate fasteners at the appropriate time.
The electrical box mounting assembly also provides the advantage that all of the load is supported by the supporting bars and the clamp, and not by the electrical box itself.
A further advantage is that the fastening hardware, while in storage in the temporary storage receptacles, does not extend beyond the outer periphery of the bars and end flanges.
These and other objects and advantages of the present invention will be better understood by reading the following description along with reference to the drawings.